SPRINGTIME MOVEMENTS, ROOST USE, AND FORAGING ACTIVITY OF TOWNSEND BIG-EARED BAT (PLECOTUS-TOWNSENDII) IN CENTRAL OREGON

Seasonal movements, roost-site fidelity, and foraging activity pattern s are largely unknown for western populations of Townsend's big-eared bat (Plecotus townsendii). We used miniature radiotelemetry units to t rack springtime movements of six bats inhabiting forested lava flows i n central Oregon, and found that bats moved up to 24 lan from hibernac ula to foraging areas. Individual bats returned to the same foraging a rea on successive nights but shifted to different areas in presumed re sponse to changes in insect availability. Both sexes apparently use a series of interim roost sites between emergence from hibernation and t he time females enter into maternity colonies, with little individual fidelity to these sites. In regions characterized by extensive lava-fl ow topography, suitable daytime roosts are numerous and dispersed over a large area, allowing bats to move relatively great distances to loc ate foraging ranges. Hence, the actual area of concern for effective m anagement of individual populations can be considerably larger than in dicated solely by locations of hibernacula and maternity caves of this declining species.